US NWS Pacific Tsunami Warning Center (PTWC)
120 Years of Earthquakes and Their Tsunamis: 1901-2020
- Title
- 120 Years of Earthquakes and Their Tsunamis: 1901-2020
- Date posted
- 2 years ago
- Description
- This animation shows every recorded earthquake in sequence as they occurred from January 1, 1901, through December 31, 2020, at a rate of 1 year per second. The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The size of each circle represents the earthquake’s magnitude while the color represents its depth within the earth. This animation also highlights significant tsunamis generated by some of these earthquakes. When the following earthquakes appear they will also have their tsunami’s “energy map” that shows each tsunami's maximum modeled wave heights on the open ocean:
8.8 — Ecuador-Columbia — 31 January 1906
8.5 — Atacama, Chile — 11 November 1922
8.4 — Kamchatka, Russia — 3 February 1923
8.4 — Sanriku, Japan — 2 March 1933
8.6 — Unimak Island, Aleutian Islands — 1 April 1946*
9.0 — Kamchatka, Russia — 4 No...
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- Tsunami Forecast Model Animation: Three Tsunamis in One Day From the Tonga-Kermadec Subduction Zone
- Date posted
- 3 years ago
- Description
- The Tonga-Kermadec Subduction Zone is a convergent boundary where the Pacific is subducted beneath the Australian Plate. It extends northeastward from New Zealand, through the Kermadec and Tonga Islands, and terminates just south of the Samoan Islands, covering a distance of about 2800 kilometers or 1800 statute miles. This boundary is also a source of large, shallow, undersea megathrust earthquakes and thus a source for tsunamis.
On 4 March, 2021, three earthquakes along this boundary each generated a tsunami within a single day. In fact, they all occurred in a little more than six hours. The first struck northeast of Gisborne, New Zealand, with a magnitude of 7.3 at 13:27 UTC. New Zealand issued tsunami warnings for its own coasts, and tsunami waves as high as 28 cm or 11 in. were observed there. Just over four hours later the second earthquake struck in the Kermadec Islands, northeast of New Zealand’s main islands, with a magnitude of 7.4 at 17:41 UTC. It also produce...
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- 40 Years of Earthquakes in the Contiguous United States: 1980 - 2020
- Date posted
- 4 years ago
- Description
- Every state and territory of the United State of America experiences earthquakes. In the contiguous states most of these earthquakes do not pose a tsunami risk as they do not lift or drop the seafloor. They are either too small, too far from a body of water, or move the underlying rock sideways. For these reasons two widely-felt earthquakes in March of 2020 also failed to generate tsunamis: the M5.7 Salt Lake City, Utah earthquake and the M6.5 Central Idaho earthquake. To put these two earthquakes in context this animation shows earthquakes in the contiguous United States for the previous forty years.
Most earthquakes in the world, including those in the United States, are “interplate” earthquakes that occur at plate tectonic boundaries where large sections of the earth’s crust either grind past each other, pull apart, or slam together. With the exception of the Pacific Coast of southern California, the contiguous United States sits atop the North American Plate. Th...
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- 30 Years of Earthquakes in Japan: 1990 - 2019
- Date posted
- 4 years ago
- Description
- The nation of Japan lies above a tectonic plate boundary called a “subduction zone” where the Pacific and Philippine Sea Plates grind beneath the Eurasian Plate. This type of plate boundary can create volcanoes, such as Japan’s many volcanoes including Mt. Fuji. Subduction zones can also generate megathrust earthquakes beneath the seafloor that cause devastating tsunamis. Many such earthquakes and tsunamis have struck Japan including the 9.1 magnitude earthquake that caused a devastating tsunami on 11 March 2011. This earthquake, the largest ever measured in Japan, produced six minutes of intense shaking starting at 14:46 local time. The tsunami that followed caused widespread devastation and over 17,000 deaths in Japan, where waves reached over 40 m or 130 ft. high. Outside of Japan the tsunami also killed one person in Papua, Indonesia and rose to greater than 5 m or 16 ft. in the Galapagos Islands (Ecuador), greater than 2m or 6.5 ft. in Indonesia, Russia's Kuril Islands, an...
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- 20 Years of Earthquakes in Chile: 2000 - 2019
- Date posted
- 4 years ago
- Description
- The nation of Chile lies above a tectonic plate boundary called a “subduction zone” where the Nazca and Antarctic Plates grind beneath the South American Plate. This type of plate boundary can create mountain belts and volcanoes, such as those that make up the Andes that stretch the entire length of the South American continent. Subduction zones can also generate megathrust earthquakes beneath the seafloor that cause devastating tsunamis. Many such earthquakes and tsunamis have struck Chile including the 8.8 magnitude earthquake that caused a devastating tsunami on 27 January 2010. This earthquake, the largest to strike Chile in 50 years, produced three minutes of intense shaking at 3:34 in the morning, killing over 400 people. The tsunami that followed caused the greatest devastation and 124 deaths on the Chilean mainland, where waves reached as high as 29 m (95 ft.). On Chile’s Juan Fernandez Islands the waves grew to over 18 m (60 ft.), killing at least 4, and over 4 m (14 ft....
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- Puerto Rico Earthquake Sequence: December 2019 - January 2020
- Date posted
- 4 years ago
- Description
- The start of 2020 saw some significant earthquake activity in the Puerto Rico region. A M6.4 earthquake struck the southern coast of Puerto Rico on January 7, killing at least one person and damaging many structures including the homes of thousands of people. It also produced a small, non-hazardous tsunami. It was preceded by a series of foreshocks in late December and followed by a sequence of aftershocks that continues today (February 2, 2020). This animation therefore begins on December 1, 2019, to show the typical level of earthquake activity prior to the start of the earthquake sequence on December 28. It proceeds forward in time at a rate of one day per second through the end of January 31.
Puerto Rico lies above an active plate boundary between the North American and Caribbean Plates. In fact, it makes up part of a “microplate” sandwiched between these two larger plates. Relative motions between these plates cause earthquakes at their boundaries. To the north t...
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- Earthquakes of the Caribbean: 2001 - 2020
- Date posted
- 4 years ago
- Description
- January 2020 saw some significant earthquake activity in the Caribbean Sea region. A M6.4 earthquake struck the southern coast of Puerto Rico on January 7 and generated a small, non-destructive tsunami. An active swarm of aftershocks continues today (January 30, 2020). A much larger M7.7 earthquake occurred between Cuba and Jamaica on January 28 and thankfully did not generate a damaging tsunami either. Though this earthquake was quite large, it moved the seafloor horizontally rather than vertically. This animation begins with the start of the 21st Century showing all earthquakes of M4 or larger as they happened and concludes with these latest earthquakes.
The Caribbean Sea lies over the Caribbean Plate, a section of the earth’s crust bounded by active faults separating it from other tectonic plates. These other plates include the North American Plate to the north and east and the Pacific Plate to the west. Relative motions between these plates cause earthquakes at thei...
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- Five Years of Earthquakes in Southern Alaska: 2015 - 2019
- Date posted
- 4 years ago
- Description
- Alaska lies above a tectonic plate boundary called a “subduction zone” such that the Pacific Plate grinds beneath the North American Plate. This type of plate boundary can create volcanoes, such as Redoubt, Augustine, and Katmai. Subduction zones can also produce megathrust earthquakes with large vertical motions that cause devastating tsunamis, such as the M9.2 Great Alaska Earthquake that struck Prince William Sound in 1964. A subduction zone boundary will also produce many smaller earthquakes, and they can be seen in this animation as the earthquakes that become deeper and deeper the further away they occur from the plate boundary, the Aleutian Trench. Meanwhile, both plates also host their own shallow earthquakes that result from many smaller faults that form as they are being squeezed and sheared by their collision in this subduction zone. In other words, there is one gigantic fault--the subduction zone megathrust--and many smaller faults on both the Pacific and North American...
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- Earthquakes of Indonesia: 2004 - 2019
- Date posted
- 4 years ago
- Description
- On 26 December 2004 the third-largest earthquake ever recorded struck the coast of Sumatra, Indonesia, with a magnitude of 9.1. It generated the deadliest tsunami in history--and one of the deadliest natural disasters--killing nearly 228,000 people in 14 countries.
Indonesia lies above a tectonic plate boundary called a “subduction zone” where the Indo-Australian Plate grinds beneath the Eurasian Plate. Subduction zones can produce megathrust earthquakes with large vertical seafloor motions that cause devastating tsunamis such as the one in 2004. This type of plate boundary can also give rise to volcanoes, and Indonesia is home to many well-known active volcanoes, such as Krakatoa, which can also generate tsunamis with their eruption and collapse.
This animation covers the 15 year period since the devastating earthquake and tsunami of 2004. It begins with a map of plate boundaries, showing the complexity of the region, and highlighting the sources of two r...
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- Earthquakes of Alaska: 1918 - 2019
- Date posted
- 4 years ago
- Description
- The M7.1 earthquake that occurred under Anchorage, Alaska, on November 30, 2018, was the largest earthquake to impact the city in 54 years. It was not, however, the largest recorded earthquake there. That distinction goes to the March 28, 1964, M9.2 Great Alaskan Earthquake (a.k.a. the Good Friday Earthquake) that struck the region as the largest earthquake ever recorded in North America, and the second-largest earthquake recorded anywhere. It in fact released more than 1000 times as much energy as the 2018 earthquake and generated a devastating tsunami.
Alaska and its Aleutian Islands lie above a tectonic plate boundary called a “subduction zone” where the Pacific Plate grinds beneath the North American Plate. This type of plate boundary can create volcanoes, such as those that make up the Aleutian Islands that stretch from Kamchatka, Russia to the Alaska Peninsula. Subduction zones can also produce megathrust earthquakes with large vertical motions that cause devasta...
- Title
- Earthquakes of the Caribbean: 1918 - 2019
- Date posted
- 4 years ago
- Description
- The M6.0 earthquake that occurred near Puerto Rico on September 24, 2019, was the largest earthquake to strike the U.S. territory in five years. It was not, however, the largest recorded earthquake there. That distinction goes to the July 7, 1943, M7.7 earthquake that thankfully did not generate a tsunami. Other earthquakes, and sometimes the landslides they cause, have produced tsunamis throughout the Caribbean Sea region, including one in Puerto Rico in 1918. Therefore this animation begins in 1918 and covers the 101 years up until the present day to show all of the recorded seismic activity in this region over that time period.*
The Caribbean Sea lies over the Caribbean Plate, a section of the earth’s crust bounded by active faults separating it from other tectonic plates. These other plates include the North American Plate to the north and east and the Pacific Plate to the west. Relative motions between these plates cause earthquakes at their boundaries. Most of the ...
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- Earthquakes of Cascadia: 1979 - 2019
- Date posted
- 4 years ago
- Description
- The widely-felt M6.3 earthquake of August 29, 2019 on the Blanco Fracture Zone was only the most recent of many moderate-size earthquakes to strike this region off of the Oregon coast. As this animation shows, such earthquakes are common along the boundaries of the Juan de Fuca plate with the Pacific Plate, which also includes the Juan de Fuca Ridge, the Gorda Ridge, and the Mendocino Fracture Zone. Fortunately these events rarely pose a tsunami hazard since the largest of these earthquakes tend to have strike-slip mechanisms that move the seafloor mostly sideways with little disruption to the ocean above.
The Juan de Fuca Plate meets the North American Plate, however, with a very different sort of plate boundary: a subduction zone. This plate boundary can produce megathrust earthquakes with large vertical motions that cause devastating tsunamis. It has been more than 300 years since the last time the Cascadia Subduction Zone generated such destruction, on January 26, 170...
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- Earthquakes of California: 1989 - 2019
- Date posted
- 4 years ago
- Description
- On July 5, 2019, the largest earthquake to strike California in 20 years occurred near the town of Ridgecrest with a moment magnitude of 7.1 following a magnitude 6.4 foreshock on the previous day. The National Tsunami Warning Center (NTWC) in Palmer, Alaska, has the primary responsibility for determining whether earthquakes in the continental United States, including California, pose a tsunami threat. The Pacific Tsunami Warning Center (PTWC) also monitors these earthquakes in case it has to provide back-up service for NTWC . While California produces many earthquakes, most are too small, too far from the ocean, and/or move the earth in such a way that they are unlikely to produce tsunamis, though there are exceptions.
This animation covers a period of 30 years to put the Ridgecrest earthquakes in context and show how they compare with other recent, noteworthy earthquakes including:
Oct 10, 1989 -- Loma Prieta -- 6.9 Mw
Apr 25, 1992 -- Cape Mendocino -...
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- Kīlauea Volcano’s Earthquakes and Eruptions: April - August, 2018
- Date posted
- 4 years ago
- Description
- The NWS’s Pacific Tsunami Warning Center (PTWC) mitigates tsunami hazards in Hawai‘i produced by large, distant earthquakes throughout the Pacific Ocean, but PTWC also issues warnings for tsunamis generated by earthquakes within the State of Hawai‘i itself. The last such dangerous tsunami was generated by a 7.7 magnitude earthquake on the Big Island of Hawai‘i in 1975. Small earthquakes generated by volcanic activity are far more common, and typically have a magnitude less than 3.0 and occur a few times a day. That rate changed on the afternoon of April 30, 2018, when an earthquake “swarm” began within Kīlauea Volcano such that earthquakes began to occur far more frequently, about 100 per day.
This animation begins a month earlier on April 1 to start with a more typical earthquake pattern and proceeds forward in time at a rate of one day per second of animation time. Circles indicate the locations of earthquakes as they occur, with their sizes indicating their...
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- Earthquakes of Hawaiʻi Island: 2013 - 2018
- Date posted
- 4 years ago
- Description
- This animation shows earthquakes on or near the Big Island of Hawaiʻi in sequence as they occurred from January 1, 2012, through December 31, 2018. Prior to 2018 the animation proceeds at a speed of one month per second, but shifts into a “slow motion” rate of one week per second for 2018 to better show the extraordinary seismic activity associated with that year’s new eruptive activity on Kīlauea Volcano, including the M6.9 earthquake on May 4 that generated a small observable, but non-life-threatening, tsunami. This animation starts in 2013 when the NEIC catalog begins to include many smaller earthquakes as it does today, thus we can see what a typical level of earthquake activity looks like prior to the elevated activity of 2018.
The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The initial size of the circle represents the earthquake’s magnitude while the ...
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- Earthquakes of the Hawaiian Islands: 1973 - 2018
- Date posted
- 5 years ago
- Description
- This animation shows earthquakes within the Hawaiian Islands in sequence as they occurred from January 1, 1973, through December 31, 2018. Prior to 2018 the animation proceeds at a speed of one year per second, but shifts into a “slow motion” rate of one month per second for 2018 to better show the extraordinary seismic activity associated with that year’s new eruptive activity on Kīlauea Volcano.
The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The initial size of the circle represents the earthquake magnitude while the color represents its depth within the earth. The animation concludes with a summary map showing all of the quakes used in this presentation.
For consistency this animation only shows those earthquakes with magnitudes 3.0 or larger, as the NEIC earthquake catalog (link below) rarely includes smaller events in Hawaiʻi prior to 2006. ...
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- Earthquakes of the 20th Century
- Date posted
- 5 years ago
- Description
- This animation shows every recorded earthquake in sequence as they occurred from January 1, 1901, through December 31, 2000, at a rate of 1 year per second. The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The size of the circle represents the earthquake magnitude while the color represents its depth within the earth. At the end of the animation it will first show all quakes in this 100-year period. Next, it will show only those earthquakes greater than magnitude 6.5, the smallest earthquake size known to make a tsunami. It will then show only those earthquakes with magnitudes of 8.0 or larger, the “great” earthquakes most likely to pose a tsunami threat when they occur under the ocean or near a coastline and when they are shallow within the earth (less than 100 km or 60 mi. deep). The animation concludes by showing the plate boundary faults responsible for the majority of all o...
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- Tsunami Animation: Hawaii 1975
- Date posted
- 5 years ago
- Description
- Not all tsunamis in the Hawaiian Islands come from overseas. On the early morning of November 29, 1975, a 7.7 magnitude* earthquake struck the southeast coast of the Big Island of Hawaii and generated a tsunami as high as 48 ft. (14.6 m). A 26 ft. (7.9 m) high wave killed two campers at the Halape Campground in Hawaii Volcanoes National Park. The tsunami also damaged property elsewhere on the Island of Hawaii and smaller non-destructive waves traveled as far as Alaska, California, Japan, and Samoa. For more information about this earthquake please see http://hvo.wr.usgs.gov/earthquakes/destruct/1975Nov29/
Our animation shows how this tsunami may have propagated in the Hawaiian Islands, transitioning at its end first to an "energy map" showing the maximum wave heights over the 6-hour period that the animation covers, then finishing with calculated tsunami runup heights on land. Note how the waves wrap around the islands and reach Honolulu in about 45 minutes. The campers i...
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- Earthquake Animation: Kīlauea Caldera - 1 April to 31 August 2018
- Date posted
- 5 years ago
- Description
- The NWS’s Pacific Tsunami Warning Center (PTWC) mitigates tsunami hazards in Hawai‘i produced by large, distant earthquakes throughout the Pacific Ocean, but PTWC also issues warnings for tsunamis generated by earthquakes within the State of Hawai‘i itself. The last such dangerous tsunami was generated by a 7.7 magnitude earthquake on the Big Island of Hawai‘i in 1975. Small earthquakes generated by volcanic activity are far more common, and typically have a magnitude less than 3.0 and occur a few times a day. That rate changed on the afternoon of April 30, 2018, when an earthquake “swarm” began within Kīlauea Volcano such that earthquakes began to occur far more frequently, about 100 per day.
This animation is shows the earthquake activity and topographic changes of Kīlauea's summit area, Kīlauea Caldera, by transitioning the map to include recent high-resolution LIDAR data in the underlying topographic relief image. It begins a month earlier on April 1 to ...
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- Context: a graphical comparison of earthquake energy release in Hawaiʻi
- Date posted
- 5 years ago
- Description
- On May 4, 2018, the largest earthquake in 43 years struck Hawaiʻi with a moment magnitude of 6.9 in the Kalapana region of the Island of Hawaiʻi (the “Big Island”). This animation puts that earthquake in historic context by comparing its magnitude with those of other earthquakes that have struck these islands in the last 150 years.
The moment magnitude number is proportional to an earthquake's total energy release such that each whole number increase in magnitude represents about a 32-fold increase in energy relase. For example, a M7 earthquake releases about 32 times as much energy as a M6 earthquake. Therefore in this animation the circle for a M7 earthquake has about 32 times the area of a M6 earthquake. Each circle is also labeled to show its magnitude, its location, and the year it happened. The animation reveals that three earthquakes are known to have been larger—that is, have released even more energy—than 2018 Kalapana earthquake. The animation concl...
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- Tsunami Forecast Model Animation: Aleutian Islands 1957
- Date posted
- 7 years ago
- Description
- At 4:22 am on Saturday, March 9, 1957 (9 March, 14:22 Z UTC) the second great earthquake in 11 years struck Alaska’s Aleutian Islands. This earthquake had the same magnitude of the earlier earthquake--8.6 on the moment magnitude scale (Johnson et al. 1994)--but was to the west of the 1946 earthquake, near the Andreanof Islands. As with the earlier event it also caused a dangerous tsunami that caused significant damage in the Aleutian Islands and in Hawaii and was observed as far away as Chile. The greatest wave heights were in Alaska’s Aleutian Islands, with waves nearly 23 m or 75 ft. high coming ashore on Unimak Island. The tsunami would reach Hawaii a little over four hours later, with the largest waves striking the island of Kauai at over 11 m or 38 ft. high and would cause $5.3 million in damage statewide ($46 million in 2017), including the destruction of more than 80 homes. Elsewhere around the Pacific Ocean the tsunami waves would reach heights of 6 m or 20 ft. in the Marqu...
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- Perspective: a graphical comparison of earthquake energy release
- Date posted
- 7 years ago
- Description
- Tsunami warning center scientists usually measure an earthquake's "size" with the moment magnitude scale rather than the older but more famous Richter magnitude scale. The moment magnitude scale is better suited for measuring the "sizes" of very large earthquakes and its values are proportional to an earthquake's total energy release, making this measurement more useful for tsunami forecasting.
Moment magnitude numbers scale such that that energy release increases by a factor of about 32 for each whole magnitude number. For example, magnitude 6 releases about 32 times as much energy as magnitude 5, magnitude 7 about 32 times as much as magnitude 6, and so on.
This animation graphically compares the relative "sizes" of some 20th and 21st century earthquakes by their moment magnitudes. Each circle's area represents its relative energy release, and its label lists its moment magnitude, its location, and the year it happened.
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Los ci...
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- Tsunami Forecast Model Animation: Sumatra 2004
- Date posted
- 7 years ago
- Description
- The magnitude 9.1 Great Sumatra-Andaman Earthquake of December 26, 2004, spawned the deadliest tsunami in history, killing more than 230,000 people in 14 countries around the Indian Ocean. More than half of those killed had lived in Acheh Province, Sumatra, where the tsunami rose as high as 30 m (100 ft.) and traveled more than 4 km (2.5 mi.) inland in this low-lying region.
This earthquake began at its epicenter near northern Sumatra and moved the earth's crust an average of 15 m (50 ft.) as it ruptured northward for at least 1200 km (750 mi.) almost to the coast of Myanmar (Burma) over an 8-minute period. This distance is at least 200 km (125 mi.) longer than the length of fault that moved during the largest earthquake ever recorded, the magnitude 9.5 Great Chile Earthquake of 1960.
This animation shows why this south-to-north rupture is important for understanding the behavior of this tsunami, and why such "progressive" rupture needs to be considered for f...
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- Earthquakes of the First 15 Years of the 21st Century
- Date posted
- 7 years ago
- Description
- This animation shows every recorded earthquake in sequence as they occurred from January 1, 2001, through December 31, 2015, at a rate of 30 days per second. The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The size of the circle represents the earthquake magnitude while the color represents its depth within the earth. At the end of the animation it will first show all quakes in this 15-year period. Next, it will show only those earthquakes greater than magnitude 6.5, the smallest earthquake size known to make a tsunami. Finally it will only show those earthquakes with magnitudes of magnitude 8.0 or larger, the “great” earthquakes most likely to pose a tsunami threat when they occur under the ocean or near a coastline and when they are shallow within the earth (less than 100 km or 60 mi. deep).
This time period includes some remarkable events. Several large earth...
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- Tsunami Forecast Model Animation: Lisbon 1755
- Date posted
- 7 years ago
- Description
- On the morning of November 1, 1755, a great earthquake shook Portugal's capital city of Lisbon as worshipers filled churches and cathedrals for the All Saints' Day Mass. In seconds it left the city in ruins and in minutes those ruins were on fire. The earthquake probably killed about 30,000 people, though some estimates double that figure. Many of the survivors fled to the wharves and keys of Lisbon's port, but they would find no safety there. The first tsunami wave surged up the Tagus estuary about an hour after the earthquake, reached a maximum runup of 12 meters (40 feet), and killed another 1000 people. At least two more tsunami waves surged into the city, completing the earthquake's destruction.
At Portugal's coastal city of Lagos the tsunami was even larger, perhaps 30 m (100 ft). It went on to damage the ports of Cadiz in Spain, then Safi and Agadir in Morocco. The tsunami also spread north: it caused minor damage at Brest in Brittany, some flooding in England in th...
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- Tsunami Forecast Model Animation: Samoa 2009
- Date posted
- 7 years ago
- Description
- At 6:48 on the morning of September 29, 2009 (17:48 UTC), an 8.1 moment magnitude earthquake struck near the Samoan Islands in the southwest Pacific Ocean. The Pacific Tsunami Warning Center (PTWC) quickly determined that the large magnitude of this earthquake, its location under the sea floor, its relatively shallow depth within the earth, and a history of tsunami-causing earthquakes in the region meant that it could have moved the seafloor and thus posed a significant tsunami risk. PTWC issued its first tsunami warning several minutes later for Samoa, American Samoa, Tonga, and other nearby island groups. The earthquake did in fact cause a dangerous tsunami, and over the following hours PTWC tracked it through the Pacific Ocean and updated its alerts with measured tsunami wave heights and recommended that additional areas consider coastal evacuation. PTWC canceled all tsunami alerts about four hours after the earthquake.
Destructive waves only struck islands near the e...
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- Tsunami Forecast Model Animation: Chile 1960
- Date posted
- 7 years ago
- Description
- On May 22, 1960, at 3:11 pm (19:11 UTC) the largest earthquake ever recorded by instruments struck southern Chile with a magnitude we now know to be at least 9.5. This earthquake generated a tsunami that traveled through every ocean on earth, though large, dangerous waves only impacted the coastlines around the Pacific Ocean. Chile suffered the greatest impact, with tsunami waves reaching as high as 25 m or 82 ft., killing an estimated 2000 people there. Outside of Chile the tsunami was worst on the opposite side of the planet in Japan, where waves reached as high as 6.3 m or over 20 ft and killed 139 people. In between and halfway across the Pacific Ocean Hawaii suffered the second-worst tsunami in its recorded history--only the Aleutian Islands tsunami of 1946 was worse. It killed 61 people in the town of Hilo with waves reaching as high as 10.7 m or about 35 ft. and all Hawaiian Islands experienced waves well over 1 m or 3 ft. The Philippines also lost 21 people to waves recorded as...
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- Tsunami Forecast Model Animation: Aleutian Islands 1946
- Date posted
- 8 years ago
- Description
- On April 1, 1946 at 4:28 am (12:28 UTC), an 8.6 moment magnitude earthquake struck off the coast of Unimak Island in Alaska’s Aleutian Islands, generating a tsunami that caused the greatest damage and number of deaths in Hawaii’s history, leading to the creation of the United States’ first tsunami warning system. As is typical for dangerous tsunamis the greatest wave heights were nearest the epicenter. The waves reached as high as 42 m or about 138 ft. on Unimak Island and destroyed its lighthouse and killed the five people there. Elsewhere this tsunami caused the greatest damage and number of deaths on inhabited Pacific islands. In Hawaii the waves reached about 17 m or 55 ft. high and killed 158 people, most in the town of Hilo, while in the Marquesas Islands in French Polynesia the waves reached even higher to 20 m or 65 ft but killed only two people. Chile’s Easter Island also got nearly 9 m or 28 ft.while its Juan Fernandez Islands got nearly 3 m or 9 ft. high waves. Pitc...
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- Tsunami Forecast Model Animation: Alaska 1964
- Date posted
- 8 years ago
- Description
- At 5:36 pm on Friday, March 27, 1964 (28 March, 03:36Z UTC) the largest earthquake ever measured in North America, and the second-largest recorded anywhere, struck 40 miles west of Valdez, Alaska in Prince William Sound with a moment magnitude we now know to be 9.2. Almost an hour and a half later the Honolulu Magnetic and Seismic Observatory (later renamed the Pacific Tsunami Warning Center, or PTWC) was able to issue its first “tidal wave advisory” that noted that a tsunami was possible and that it could arrive in the Hawaiian Islands five hours later. Upon learning of a tsunami observation in Kodiak Island, Alaska, an hour and a half later the Honolulu Observatory issued a formal “tidal wave/seismic sea-wave warning” cautioning that damage was possible in Hawaii and throughout the Pacific Ocean but that it was not possible to predict the intensity of the tsunami. The earthquake did in fact generate a tsunami that killed 124 people (106 in Alaska, 13 in California, and 5 in O...
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- Tsunami Forecast Model Animation: Japan 2011
- Date posted
- 8 years ago
- Description
- At 14:46 on the afternoon of 11 March 2011 (05:46 UTC), a 9.0 moment magnitude earthquake struck near the coastline of Honshu, Japan. The Pacific Tsunami Warning Center (PTWC) quickly determined that the very large magnitude of this earthquake, its offshore location, its relatively shallow depth within the earth, and a history of megathrust earthquakes in the region meant that it likely moved the seafloor and thus posed a significant tsunami risk. As per international agreements Japanese authorities issued tsunami warnings for their own coastlines while PTWC began issuing warnings to other countries and territories in the western Pacific Ocean. The earthquake did in fact cause a tsunami, and over the following hours as PTWC learned more about the earthquake (confirming it was a megathrust and upgrading its magnitude) and its tsunami through forecast models and direct observation with DART sensors and coastal sea-level gauges PTWC would eventually issue tsunami warnings to the State of ...
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- Tsunami Forecast Model Animation: Chile 2010
- Date posted
- 8 years ago
- Description
- At 3:34 on the morning of February 27, 2010 (06:34 UTC), an 8.8 moment magnitude earthquake struck near the coastline of central Chile. The Pacific Tsunami Warning Center (PTWC) quickly determined that the large magnitude of this earthquake, its location near the coastline, its relatively shallow depth within the earth, and a history of megathrust earthquakes in the region meant that it could have moved the seafloor and thus posed a significant tsunami risk and PTWC issued their first tsunami warning several minutes later for Chile and Peru. The earthquake did in fact cause a tsunami, and over the following hours as PTWC learned more about the earthquake (confirming it was a megathrust and upgrading its magnitude) and its tsunami through forecast models and direct observation with DART sensors and coastal sea-level gauges PTWC would eventually issue tsunami warnings to the State of Hawaii and all 43 countries and territories participating the Pacific Tsunami Warning System, keeping war...
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- Tsunami Forecast Model Animation: Cascadia 1700
- Date posted
- 8 years ago
- Description
- Just before midnight on January 27, 1700 a tsunami struck the coasts of Japan without warning since no one in Japan felt the earthquake that must have caused it. Nearly 300 years later scientists and historians in Japan and the United States solved the mystery of what caused this “orphan tsunami” through careful analysis of historical records in Japan as well as oral histories of Native Americans, sediment deposits, and ghost forests of drowned trees in the Pacific Northwest of North America, a region also known as Cascadia. They learned that this geologically active region, the Cascadia Subduction Zone, not only hosts erupting volcanoes but also produces megathrust earthquakes capable of generating devastating, ocean-crossing tsunamis. By comparing the tree rings of dead trees with those still living they could tell when the last of these great earthquakes struck the region. The trees all died in the winter of 1699-1700 when the coasts of northern California, Oregon, and Washingto...
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- Tsunami Animation: Valdivia, Chile, 1960 (rotating globe)
- Date posted
- 8 years ago
- Description
- The largest earthquake ever recorded by instruments struck southern Chile on May 22, 1960. This 9.5 magnitude earthquake generated a tsunami that crossed the Pacific Ocean, killing as many as 2000 people in Chile and Peru, 61 people in Hilo, Hawaii, and 142 people in Japan as well as causing damage in the Marquesas Islands (Fr. Polynesia), Samoa, New Zealand, Australia, the Philippines, and in Alaska's Aleutian Islands.
Our animation adapts the earthquake source of Fujii and Satake (2012) to show how this tsunami may have propagated in the Pacific Ocean. The animation ends with a transition to an "energy map" summarizing the changes in open-ocean sea level height predicted by our real-time tsunami forecast model (RIFT).
To see how this tsunami compares with two recent tsunamis from Chile, please watch http://youtu.be/qoxTC3vIF1U
(Mercator version: https://youtu.be/oeKewmAoBEM)
- Title
- ¡Alerta de tsunami!
- Date posted
- 8 years ago
- Description
- Cuando un terremoto submarino ocurre cerca de la costa el mismo puede generar un maremoto destructivo que golpeará las costas cercanas en minutos, y que también viajará a lo largo y ancho del oceáno causando daños a miles the kilómetros de distancia, incluso 24 horas más tarde. Para alertar a las costas lejanas, sistemas de alertas internacionalmente coordinados, como el Sistema de Alertas y Mitigación de Tsunamis del Pacífico (PTWS), se han establecido para proveer a los diferentes países con información acerca del peligro de tsunamis.
2015 marca el 50 aniversario de la fundación del PTWS. El sistema se estableció en 1965 en respuesta al terremoto con magnitud 9.5 de 1960 ocurrido en la vecindad de la región centro-Sur de Chile, el cual generó un tsunami que cruzó el Pacífico matando a cientos de personas en Hawaii, Japón, y Las Filipinas. El PTWS se ha edificado a lo largo de varias décadas gracias a la cooperación internacional y contribuciones de l...
- Title
- Alerte aux tsunamis!
- Date posted
- 8 years ago
- Description
- Quand un séisme sous-marin se produit près de la côte, il peut générer un tsunami destructeur qui pourrait affecter les côtes à proximité dans quelques minutes, et se rendra également à ravers l'océan causant des dommages à des milliers de kilomètres même 24 heures plus tard. Pour alerter les côtes lointaines, les systèmes d'alerte coordonnés au niveau international, tels que le système d'alerte aux tsunamis dans le Pacifique (PTWS), ont été mis en place pour fournir des différents paysavec des informations sur le danger des tsunamis.
2015 marque le 50e anniversaire de la fondation de la PTWS. Le système a été créé en 1965 en réponse à un tremblement de terre de magnitude 9,5 arrivé en 1960 dans le environs de la région centre-sud du Chili qui a généré un tsunami qui a traversé le Pacifique tuant des centaines de personnes à Hawaï, au Japon et aux Philippines. Le PTWS a été construit au cours des décennies grâce à la coopération in...
- Title
- Tsunami Warning!
- Date posted
- 8 years ago
- Description
- When a major undersea earthquake occurs near the coast, a destructive tsunami can result that will hit near-by coasts in minutes and also travel across entire oceans causing damage 1000’s of kilometers away and up to 24 hours later. To alert far-away coasts, internationally coordinated tsunami early warning systems, such as the Pacific Tsunami Warning and Mitigation System (PTWS), have been established to quickly provide tsunami threat information to countries.
2015 marks the 50th year of the PTWS. The System was established in 1965 in response to the 1960 M9.5 earthquake off South-central Chile that generated a tsunami which crossed the Pacific killing hundreds in Hawaii, Japan, and the Philippines. The PTWS has been built up over the decades through international cooperation and the contributions of countries and organizations under the UNESCO IOC framework.
To sustain awareness on the dangers of tsunamis, and to educate the public on how the PTWS works to...
- Title
- Five Years of Earthquakes in Chile
- Date posted
- 9 years ago
- Description
- The 8.8 magnitude 27 February 2010 earthquake in central Chile was the largest in that country in 50 years. This animation shows that earthquake and all those recorded there in the following five years, including the 8.2 magnitude earthquake in northern Chile on 1 April 2014.
For animations of the tsunamis generated by these two great earthquakes please see:
2010, central Chile: http://youtu.be/RO16edaxoV0
2014, northern Chile: http://youtu.be/hhvfbjCIiXo
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El terremoto con magnitud 8.8 ocurrido el 27 de Febrero del 2010 in la region central de Chile constituye el más grande registrado en ese país en los últimos 50 años. Esta animación muestra ese terremoto y todos los registrados en los últimos cinco años, incluyendo el terremoto de magnitud 8.2 ocurrido al Norte de Chile el 1 de Abril del 2014.
Para ver las animaciones de los tsunamis generados por estos dos grandes terromotos por favor vea:
- Title
- A Decade of Tsunami Warning System Sensor Network Upgrades
- Date posted
- 9 years ago
- Description
- The best-known tsunami-detection devices are the DART buoys. These buoys transmit data from their pressure sensors on the sea floor that measure tsunami waves passing over them. In 2004 we had only 8 DARTs, all in the Pacific Ocean. Today we use more than 60 DARTs worldwide.
In addition to DARTs we also measure tsunamis with sea-level gauges located on coastlines. In 2004 we received sea-level data from about 150 of these coastal gauges, mostly in and around the Pacific Ocean. Today we receive sea-level data from more than 600 coastal gauges worldwide.
Long before we can measure a tsunami we can detect and locate the earthquake that caused it. Therefore we use a global network of seismometers to record earthquakes as they occur and determine their tsunami-causing potential in real time. In 2004 we analyzed seismic data from about 120 seismometers worldwide. Today we use more than 650 seismometers worldwide.
We can determine how these additional se...
- Title
- A Decade of Great Earthquakes
- Date posted
- 9 years ago
- Description
- December 2014 includes the 10-year anniversary of the 9.1 magnitude Sumatra-Andaman earthquake that generated the 2004 Indian Ocean Tsunami, one of the worst disasters in history with a death toll exceeding 200,000 people. In the decade following this event there have been many more tsunamis triggered by great earthquakes, and this animation shows all earthquakes in sequence at a speed of 30 days per second from 1 December 2004 to 30 November 2014, concluding with a map showing all earthquakes recorded in this span of time. It then transitions to a map showing just those earthquakes with magnitude 6.5 or greater (about 500 total), the smallest size known to generate a dangerous tsunami and thus the threshold PTWC typically uses to begin assessing tsunami risk. It then transitions one more time to a map showing earthquakes with magnitude 8.0 or greater (17 total), the "great" earthquakes that are most likely to pose a tsunami hazard if they occur near the sea floor.
- Title
- Tsunami Animation: Sumatra, 2004
- Date posted
- 9 years ago
- Description
- The magnitude 9.1 Great Sumatra-Andaman Earthquake of December 26, 2004, spawned the deadliest tsunami in history, killing more than 230,000 people in 14 countries around the Indian Ocean. More than half of those killed had lived in Acheh Province, Sumatra, where the tsunami rose as high as 30 m (100 ft.) and traveled more than 4 km (2.5 mi.) inland in this low-lying region.
This earthquake began at its epicenter near northern Sumatra and moved the earth's crust an average of 15 m (50 ft.) as it ruptured northward for at least 1200 km (750 mi.), almost to the coast of Myanmar (Burma), over an 8-minute period. This distance is at least 200 km (125 mi.) longer than the length of fault that moved during the largest earthquake ever recorded, the magnitude 9.5 Great Chile Earthquake of 1960.
This animation shows why this south-to-north rupture is important for understanding the behavior of this tsunami, and why such "progressive" rupture needs to be considered for...
- Title
- Tsunami Animation: Three Tsunamis From Chile
- Date posted
- 9 years ago
- Description
- This side-by-side comparison of three tsunamis generated within the same region highlights two important characteristics of tsunami behavior.
First, the height of the tsunami waves (as shown by color) is strongly dependent on the size of the earthquake, namely its moment magnitude (Mw). The 9.5 Mw earthquake of 1960 released approximately 11 times more energy than the 8.8 Mw earthquake of 2010 and approximately 89 times more energy than the 8.2 Mw earthquake of 2014. Likewise, the tsunami wave heights were far larger in 1960 than they were in 2010, and larger in 2010 than they were in 2014.
Second, the speed of a tsunami does not depend on the size of the earthquake. All three tsunamis move at about the same speed regardless of their size because their waves are so large that they interact with the sea floor. Therefore, both the ocean depth and its local variations control the speed of the tsunami waves.
These two characteristics are critical ...
- Title
- Global Earthquake Animation: January - April 2014
- Date posted
- 10 years ago
- Description
- Earthquakes happen every day, and as this animation shows, small ones happen more frequently than once per hour. Moderate-to-large earthquakes are less common, however, perhaps 1-2 per month on a long-term average. Therefore April 2014 was unusual not in the total number of earthquakes that occurred but in how many moderate and large ones happened, and PTWC had to issue official message products for 13 different earthquakes in that month for earthquakes with magnitudes of 6.5 or higher, easily a record for this institution. Of those 13, PTWC issued tsunami warnings for 5:
1 April, M8.2, northern Chile
3 April, M7.8, northern Chile
12 April, M7.6, Solomon Islands
13 April, M7.7, Solomon Islands
19 April, M7.8, Solomon Islands
This animation shows all earthquakes on earth so far this year in sequence as recorded in the USGS's NEIC database (available at earthquake.usgs.gov). Note the typical level of activity through March. But s...
- Title
- Tsunami Animation: Iquique, Chile, 1 April 2014
- Date posted
- 10 years ago
- Description
- PTWC's near real-time animation for the tsunami from northern Chile on 1 April 2014 resulting from an offshore 8.2 magnitude earthquake in the region. The animation shows simulated tsunami wave propagation for 30 hours followed by an "energy map" showing the maximum open-ocean wave heights over that period and the forecasted tsunami runup heights on the coastlines.
- Title
- Tsunami Animation: Unimak Island, Aleutian Islands, 1946 (rotating globe)
- Date posted
- 10 years ago
- Description
- The Eastern Aleutian earthquake of April 1, 1946 spawned Hawaii's most damaging tsunami. The tsunami flooded all coastlines of all islands and resulted in 159 deaths. The tsunami arrived at about 6:45 a.m. local time and caught many people in Hilo in their houses; there were 96 deaths in that city alone. The tsunami was remarkable elsewhere in the Pacific as well. In the Marquesas, where, fortunately, it arrived late in the morning and so was widely recognized (only three people died there), the waves ran up on shore to a maximum elevation of 65 feet. In Hawaii the waves had reached "only" to 54 feet, on the north shore of Molokai.
The earthquake itself has always been an enigma. At the time it seemed that its magnitude was 7.4. Modern corrections have increased that number substantially, but the official magnitude listed by the US Geological Survey is still only 8.1. In a careful analysis of the very few seismograms recording very long period energy, Lopéz and Okal in 20...
- Title
- Tsunami Animation: Prince William Sound, Alaska, 1964 (virtual globe)
- Date posted
- 10 years ago
- Description
- One of the largest earthquakes ever recorded by instruments (and the largest ever in the United States) struck south-central Alaska on March 27, 1964 (local time). This 9.2 magnitude earthquake generated a tsunami that killed people in Alaska and California and damaged property in those states as well as in British Columbia, Oregon, and Hawaii. Our animation shows how that tsunami may have propagated in the Pacific Ocean 50 years ago and covers a 20-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves followed by the forecasted tsunami runup on the coasts.
As part of its response to this event the United States government created a second tsunami warning center in 1967, the Alaska Tsunami Warning Center--now called the National Tsunami Warning Center--to help mitigate future tsunami threats to Alaska, Canada, and the U.S. Mainland. Please see http://ntwc.arh.noaa.gov/ for more information about our sister Center.
- Title
- Tsunami Animation: Tohoku, Japan 2011 (rotating globe)
- Date posted
- 10 years ago
- Description
- This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 9.0 magnitude earthquake offshore of the Tōhoku-Oki region, Japan, on 11 March 2011. This version uses the USGS finite fault model (link below) as the source mechanism for the tsunami model, therefore the animation begins in "slow motion" to show the details of how the tsunami starts. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts. If you look carefully you will see not only the waves leaving Japan, but also the reflected waves leaving South America after about 23 hours.
For a "flat earth" version, please see: http://youtu.be/EG507Y40d4U
For the earthquake and its aftershocks, please see: http://youtu.be/3r-JVx8yMpw
Finite fault model: http://earthquake.usgs...
- Title
- Tsunami Animation: Tohoku, Japan 2011 (Mercator)
- Date posted
- 10 years ago
- Description
- This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 9.0 magnitude earthquake offshore of the Tōhoku-Oki region, Japan, on 11 March 2011. This version uses the USGS finite fault model (link below) as the source mechanism for the tsunami model, therefore the animation begins in "slow motion" to show the details of how the tsunami starts. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts. If you look carefully you will see not only the waves leaving Japan, but also the reflected waves leaving South America after about 23 hours.
For a "rotating globe" version, please see: http://youtu.be/feBtPsJH25c
For the earthquake and its aftershocks, please see: http://youtu.be/3r-JVx8yMpw
Finite fault model: http://earthquake....
- Title
- Tsunami Animation: Maule, Chile 2010 (rotating globe)
- Date posted
- 10 years ago
- Description
- This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 8.8 magnitude earthquake in Maule, Chile on 27 February 2010. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts.
For the earthquake and its aftershocks, please see: http://youtu.be/hBhYV3B8_bw
- Title
- Tsunami Animation: Maule, Chile 2010 (Mercator)
- Date posted
- 10 years ago
- Description
- NEW VERSION AT https://youtu.be/oeKewmAoBEM
This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 8.8 magnitude earthquake in Maule, Chile on 27 February 2010. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts.
For a "rotating globe" version, please see: http://youtu.be/L2mz-dETib8
For the earthquake and its aftershocks, please see: http://youtu.be/hBhYV3B8_bw
- Title
- Meteotsunami Animation: U.S. East Coast, June 2013
- Date posted
- 10 years ago
- Description
- PTWC scientists used their tsunami forecast model, RIFT, to simulate how a weather-generated tsunami, or meteotsunami, may have propagated off of the east coast of the United States in the north Atlantic Ocean on June 13, 2013. A "derecho," or a rapidly-moving coherent storm front, traveled eastward across the US's mid-Atlantic states and out over the ocean as an atmospheric pressure anomaly. It appears in the animation as a prominent "negative" wave or trough in the sea's surface. It generates meteotsunami waves as it moves, and when it reaches the edge of the continental shelf (seen as a change from light blue to darker blue colors in the ocean) the waves jump or "spike" in amplitude there and propagate along the shelf's edge. The meteotsunami waves reflect landward from the shelf's edge due to the rapid change in wave velocity there (tsunami waves travel much faster in deeper water), then reflect again seaward from the coastline. Thus these waves become trapped in the shallow wa...
